Problem: Express your answer as a mixed number simplified to lowest terms. $19\dfrac{1}{3}-1\dfrac{9}{10} = {?}$
Answer: Find a common denominator for the fractions: $= {19\dfrac{10}{30}}-{1\dfrac{27}{30}}$ Convert ${19\dfrac{10}{30}}$ to ${18 + \dfrac{30}{30} + \dfrac{10}{30}}$ So the problem becomes: ${18\dfrac{40}{30}}-{1\dfrac{27}{30}}$ Separate the whole numbers from the fractional parts: $= {18} + {\dfrac{40}{30}} - {1} - {\dfrac{27}{30}}$ Bring the whole numbers together and the fractions together: $= {18} - {1} + {\dfrac{40}{30}} - {\dfrac{27}{30}}$ Subtract the whole numbers: $=17 + {\dfrac{40}{30}} - {\dfrac{27}{30}}$ Subtract the fractions: $= 17+\dfrac{13}{30}$ Combine the whole and fractional parts into a mixed number: $= 17\dfrac{13}{30}$